Method for transmitting and receiving paging information in a broadband wireless access system

ABSTRACT

A method for efficiently transmitting and receiving a paging message and system information from and in a mobile station of a broadband wireless access system is disclosed. A method for receiving a paging message in a mobile station comprises receiving paging information from a serving base station, the paging information including paging sub group identifier (paging sub group ID) indicating a paging sub group to which the mobile station belongs; and receiving the paging message for a predetermined paging interval of the paging sub group, wherein the paging sub group is determined separately from a paging group and a geographical location determining the paging group, and is maintained while the mobile station is being operated in an idle mode.

TECHNICAL FIELD

The present invention relates to a broadband wireless access system, andmore particularly to, a method for transmitting and receiving paginginformation efficiently.

BACKGROUND ART

In the following description, a generally used paging group and an idlemode of a terminal are schematically explained.

FIG. 1 is a diagram illustrating a paging group in a general IEEE 802.16system.

Referring to FIG. 1, a plurality of base stations (BS) supporting anidle mode belong to a paging group to construct a paging area.

In this case, the paging group indicates a logical group. If there is atraffic that targets a mobile station (MS), the object of the paginggroup is to provide a neighbor range area that can be paged in downlink(DL). And, the paging group should meet the condition to be large enoughfor a specific terminal to exist for most of time within a same paginggroup and the condition to be small enough for a paging load to maintaina proper level.

FIG. 1 shows four paging groups defined on multiple base stationslocated at hexagonal lattices. One base station is able to be includedin one or more paging groups. The paging group is defined by amanagement system. And, a paging group is able to use a paginggroup-action backbone network message. Moreover, a list of terminal inidle mode is managed using a paging-announce message corresponding toone of backbone network messages and initial paging of all base stationsbelonging to a paging group can be managed.

Idle mode indicates an operation of supporting a terminal toperiodically receive a downlink (DL) broadcast traffic transmissionwithout registering at a specific base station when the terminal ismoving in a wireless link environment constructed with multiple basestations.

Idle mode is able to give the benefit to a terminal by eliminating ahandover-related activation requirement and general operationrequirements. Idle mode is able to save power and operational resourcesused by a terminal in a manner of put limitation on a terminal action tobe scanned in a discrete cycle.

Idle mode provides a simple and proper method of informing a terminalfor a downlink traffic in pending and is able to give the benefit to anetwork and a base station by removing a wireless interface and anetwork handover (HO) traffic from an inactive terminal.

Hereinafter, an example of an operation procedure of a mobile stationentering an idle mode in a general IEEE 802.16 system will be describedwith reference to FIG. 2. Referring to FIG. 2, a mobile station cantransmit a deregistration request (DREG-REQ) message to a serving basestation to enter an idle mode from a normal mode (S201).

The serving base station which has received the DREG-REQ message cantransmit and receive information of the mobile station and the servingbase station to and from a paging controller. Namely, the serving basestation can notify the paging controller of mobile station identifier(MSID) and serving base station identifier (BSID). Also, the pagingcontroller can notify the serving base station of paging groupidentifier (PG ID) or paging controller identifier (PC ID). The paginggroup identifier or the paging controller identifier can be used totransmit and receive a paging message.

Subsequently, the serving base station can transmit a deregistrationcommand (DREG-CMD) message to the mobile station. The serving basestation can transmit the deregistration command (MOB_DREG-CMD) messageto the mobile station in response to the deregistration request message.The deregistration command message can include paging information. Atthis time, the paging information can include parameters such as pagingcycle, paging offset, and paging listening interval. The deregistrationcommand message can further include paging controller identifier andpaging group identifier (S203).

At this time, the paging information can be included in thederegistration command message in a type of Table 7 below. Thisinformation can be provided to the mobile station through a rangingresponse (RNG-RSP) message in a location update procedure which will bedescribed later.

TABLE 1 Type Length Value Scope 134 7 Bits #0-15: PAGING_CYCLE - cyclein which the paging RNG-RSPDREG- message is transmitted within thepaging group. Bits CMD 

#16-31: PAGING_OFFSET - determines the frame within the cycle from whichthe paging interval starts. Shall be smaller than PAGING_CYCLE value.Bits #32-47: Paging-group-ID- ID of the paging group the MS is assignedto. Bits #48-55: Paging Interval Length - Max duration in frames ofPaging Listening interval. Used in calculation of Paging listeninginterval. value shall be between 1 and 5 frames (default = 2). 

The parameters in Table 1 are user equipment-specific values, anddifferent paging cycles, paging offsets and paging listening intervalscan be allocated to the respective mobile stations. The base station canidentify a paging interval of each mobile station through theparameters.

The mobile station which has received the DREG-CMD message from theserving base station identifies that a request of entrance to an idlemode is successfully accepted, and enters the idle mode. The mobilestation can receive a paging message based on paging informationreceived through the MOB_DREG-CMD message.

Namely, the mobile station can monitor a radio channel to identify thepresence of a paging message transferred thereto for a paging listeninginterval. The mobile station is operated in a sleep mode (or the radiochannel is turned off) for the other interval to reduce powerconsumption (S204).

A call or external packet can be transmitted to the paging controller(S205).

In this case, the paging controller can perform a paging procedure ofthe mobile station. At this time, the paging controller can transmit apaging announcement message to all base stations within the paging group(S206).

All the base stations within the paging group, which have received thepaging announcement message, can broadcast a MOB_PAG-ADV message to allmobile stations managed by the base stations. At this time, the pagingmessage can include parameters of Table 2 (S207).

TABLE 2 Syntax 

Size (bit) 

Notes for (i = 0; i < Num_Paging_Group_IDs; — — i++) { 

Paging Group ID 

— 16 } — — Num_MACs 

— Number of MS MAC addresses 

For (j = 0; j < Num_MACs; j++) { 

— — MS MAC Address hash 

24  The hash is obtained by computing a CRC24 on the MS 48-bit MACaddress. The polynomial for the calculation is 0x1864CFB 

Action Code 

2 Paging action instruction to MS 0b00 = No action required 0b01 =Perform ranging to establish location and acknowledge message 0b10 =Enter network 0b11 = Reserved 

Reserved 

6 — } — — Padding 

variable 

Padding bits to ensure octet aligned 

TLV Encoded Information 

variable 

TLV-specific 

} —

The mobile station checks the MOB_PAG-ADV message. If the mobile stationis paged by the paging controller, the mobile station enters a normalmode and is then able to perform communications with the serving basestation (S208, S209).

In a general communication system, mobile stations belonging to the samepaging group can have different paging intervals. These paging intervalscan be managed by the paging controller or the base station. The pagingintervals will be described with reference to FIG. 3.

FIG. 3 is a diagram illustrating different paging intervals of twodifferent mobile stations, which belong to the same paging group in ageneral communication system.

Referring to FIG. 3, it is assumed that two mobile stations MS1 and MS2exist in the same paging group. At this time, in the mobile station MS1,the first frame of the paging cycle can be established as a paginginterval, and in the mobile station MS2, the fourth frame of the samepaging cycle can be established as a paging interval.

Next, a procedure of updating system information in a mobile stationwhich is in an idle mode will be described.

The mobile station which is in the idle mode wakes up for only alistening interval and then receives a paging message. Subsequently, themobile station takes a corresponding action in accordance with an actioncode value. For example, if an action code corresponding to the mobilestation is ‘0’, the mobile station does not take any action. If anaction code corresponding to the mobile station is ‘1’, the mobilestation can perform ranging for location update.

It is assumed that a downlink channel descriptor (DCD) message, anuplink channel descriptor (UCD) message or neighboring cell informationtransmitted from a preferred base station of the mobile station which isin the idle mode is updated. At this time, in a general wirelesscommunication system, the preferred base station can notify the mobilestation of a frame where a message containing the updated DCD/UCD orneighboring cell information is transmitted by transmitting a broadcastcontrol pointer information element (Broadcast_Control_Pointer_IE) tothe mobile station. Table 3 illustrates contents that can be included inthe broadcast control pointer information element.

TABLE 3 Syntax Size (bit) 

Notes Broadcast_Control_Pointer_IE( — — ) { 

Extended DIUC 

4 Broadcast_Control_Pointer_IE( ) = 0xA 

Length 

4 Length in bytes 

DCD_UCD Transmission 7 The most significant bits of the frame Frame 

number's least 9 significant bits of the next DCD and/or UCDtransmission. 

Skip Broadcast_System_Update 1 —

If (Skip — — Broadcast_System_Update == 0) { 

Broadcast_System_Update_Type 1 Shows the type of

Broadcast_System_Update0: For MOB_NBR-ADV Update 1: For EmergencyServices Message 

Broadcast_System_Update_Transmission _Frame 

7 The least significant bits of the frame number of the nextBroadcast_System_Update transmission. 

} — — } — —

Referring to Table 3, the broadcast control pointer information elementcan include information of a frame (DCD_UCD transmission frame) wherethe DCD/UCD messages are transmitted, and a frame(broadcast_system_update_transmission_frame) for update of broadcastsystem information.

Unlike the mobile station which is in an active mode, the mobile stationwhich is in the idle mode can receive a message by waking up for only alistening interval. Since the updated DCD or UCD message has arelatively great transmission cycle (maximum ten seconds), if theupdated message is not transmitted within the listening interval of eachmobile station, each mobile station may not receive the updated message.Such a case will be described with reference to FIG. 4.

FIG. 4 is a diagram illustrating an operation procedure of updatingsystem information through a mobile station, which is in an idle mode,in a general communication system.

Referring to (a) of FIG. 4, the mobile station can receive the broadcastcontrol pointer information element from the preferred base station foronly its listening interval. The mobile station can wake up to receivethe updated system information even if a frame indicated by thebroadcast control pointer information element does not correspond to thelistening interval of the mobile station. The mobile station can againsleep until next listening interval if the updated system information issuccessfully received.

However, it may be assumed that the mobile station fails to receive theupdated system information from the frame indicated by the broadcastcontrol pointer information element as illustrated in (b) of FIG. 4. Atthis time, the mobile station may have to receive system information bywaking up until next interval where system information is transferred.

DISCLOSURE OF INVENTION Technical Problem

In a general broadband wireless access system, a paging controller thatmanages a paging procedure of a mobile station should report paginginformation (paying cycle, paging offset, paging interval, etc.) of acorresponding mobile station to a base station if the mobile station ispaged. This is because that the base station can exactly transmit apaging message to the corresponding mobile station only when knowing aninterval where the mobile station wakes up.

In the worst case, a base station may have to transmit the pagingmessage every frame in accordance with a distribution of pagingintervals of mobile stations which are in idle mode.

Furthermore, even though a mobile station which is in an idle mode knowsa frame where system information is transmitted by successfullyreceiving a broadcast control pointer information element (IE) from apreferred base station so as to update system information, the mobilestation may fail to receive the system information.

Moreover, it is assumed that sub maps are multiplexed with one cyclicredundancy check (CRC) in a general system (for example, IEEE 802.16esystem), like a downlink map or an uplink map (DL/UL-MAP). In this case,the mobile station waking up from a paging subframe should decode thewhole sub maps. Also, if the sub maps are transmitted through a separateCRC attachment in accordance with connection identifier (CID) (forexample, CRC or CID masking), the mobile station performs blind decodingfor all sub maps through corresponding CID in a general system (forexample, long term evolution (LTE) system), thereby detecting controlsignals transmitted thereto. In case of a general wireless communicationsystem, broadcast CID is used to transmit a paging message. If themessage is transmitted using broadcast CID, the mobile stations whichare in a normal mode as well as the mobile stations which are in an idlemode may all receive the paging message. If the mobile station which isin a normal mode receives a paging message, it causes unnecessary powerconsumption of the mobile station and increases decoding overhead of themobile station.

The present invention is devised to substantially obviate one or moreproblems due to limitations and disadvantages of the related art. Anobject of the present invention is to provide method for efficientlyupdating system information in a mobile station which is in an idlemode.

Another object of the present invention is to provide a method forefficiently paging a mobile station.

Other object of the present invention is to provide an operation methodfor efficiently saving the power of a mobile station.

It is to be understood that the technical problems to be achieved by thepresent invention are not limited to the aforementioned problems andother technical problems which are not mentioned will be apparent fromthe following description to the person with an ordinary skill in theart to which the present invention pertains.

Technical Solution

In order to solve the above technical problems, the present inventionprovides various methods for efficiently transmitting and receiving apaging message.

In one aspect of the present invention, a method for receiving a pagingmessage in a mobile station comprises receiving paging information froma serving base station, the paging information including paging subgroup identifier (paging_sub_group_ID) indicating a paging sub group towhich the mobile station belongs; and receiving the paging message for apredetermined paging interval of the paging sub group, wherein thepaging sub group is determined separately from a paging group and ageographical location determining the paging group, and is maintainedwhile the mobile station is being operated in an idle mode.

At this time, the paging interval is established in a subframe unit.

Also, the method further comprises receiving paging indicationinformation indicating whether a paging message of at least one pagingsub group is transmitted. In this case, the step of receiving the pagingmessage is performed when the paging indication information indicatesthe paging sub group to which the mobile station belongs.

Also, the paging indication information includes at least one of bitsindicating whether the paging message of at least one paging sub groupis transmitted, and if the paging indication information is transmittedtwice or more within the paging cycle, the paging indication informationis transmitted at different superframes.

Also, the paging indication information is transmitted at a firstsubframe of a superframe where a paging cycle starts, through any one ofa superframe header (SFH), a broadcast channel (BCH) included in thesuperframe header, a data region of the first subframe, and a sub-packetof a secondary superframe header.

Also, the paging interval is a subframe after predetermined offsetestablished in accordance with the paging sub group from the subframefrom which the paging indication information is transmitted.

Also, the bits respectively represent whether the paging message of onepaging sub group is transmitted, and if the paging indicationinformation includes bits of all paging sub groups belonging to apredetermined paging group, the paging information is broadcasted to themobile station through the superframe header.

Also, the paging message further includes a system information updateindication (SIUI) field, the method further comprises performing updateof system information if the SIUI field indicates update of the systeminformation.

Also, the step of performing update of system information includesacquiring system information by decoding a superframe header (SFH)received after a superframe where the paging message including thesystem information update indication field is transmitted.

Also, the paging message is transmitted to the mobile station through adownlink resource indicated by predetermined paging message controlinformation included in a sub-map of a subframe corresponding to thepaging interval, the predetermined paging message control information isCRC masked by predetermined paging CID for a specific mobile station ofan idle mode, and the mobile station performs blind decoding for thepredetermined paging message control information using its paging CID.

Also, the predetermined paging message control information has a sizepreviously established in a previously established location of thesub-map.

In another aspect of the present invention, a method for transmitting apaging message from a base station to a mobile station comprisesreceiving a deregistration request message from the mobile station;transmitting a deregistration command message including paginginformation to the mobile station, the paging information includingpaging sub group identifier (paging_sub_group_ID) indicating a pagingsub group to which the mobile station belongs; and transmitting a pagingmessage to the mobile station for a predetermined paging interval of thepaging sub group, wherein the paging sub group is established separatelyfrom a paging group and a geographical location determining the paginggroup, and is maintained while the mobile station is being operated inan idle mode.

At this time, the paging interval is established in a subframe unit.

Also, the method further comprises receiving a paging indication messageof the mobile station from a paging controller; and transmitting pagingindication information to the mobile station, the paging indicationinformation indicating whether a paging message of a paging sub group towhich the mobile station belongs is transmitted.

Also, the paging indication information is transmitted from a firstsubframe of a superframe where a paging cycle starts, through any one ofa superframe header (SFH), a broadcast channel (BCH) included in thesuperframe header, a data region of the first subframe, and a sub-packetof a secondary superframe header.

Also, the step of transmitting a paging message is performed at asubframe after predetermined offset previously determined for a pagingsub group to which the mobile station belongs, from a subframe where thepaging indication information is transmitted.

In other aspect of the present invention, a method for receiving apaging message in a mobile station of an idle mode comprises monitoringthe paging message for a first paging cycle; and increasing the firstpaging cycle by a predetermined value if the paging message is notreceived for the first paging cycle.

At this time, the step of monitoring the paging message and the step ofincreasing the first paging cycle are repeated as much as the number oftimes, which is previously determined.

Also, the step of increasing the first paging cycle is performed untilthe first paging cycle becomes equal to a maximum paging cycle which ispreviously determined.

Advantageous Effects

According to the present invention, the following advantages can beobtained.

First of all, the mobile station which is in the idle mode can updatesystem information more efficiently.

Second, it is possible to page the mobile station which is in the idlemode, more efficiently.

Finally, the mobile station can be operated in the idle mode moreefficiently.

It is to be understood that the advantages that can be obtained by thepresent invention are not limited to the aforementioned advantages andother advantages which are not mentioned will be apparent from thefollowing description to the person with an ordinary skill in the art towhich the present invention pertains.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a paging group in a general IEEE 802.16system;

FIG. 2 is a diagram illustrating an example of an operation procedure ofa mobile station which enters an idle mode in a general IEEE 802.16system;

FIG. 3 is a diagram illustrating paging intervals of two differentmobile stations belonging to the same paging group in a generalcommunication system;

FIG. 4 is a diagram illustrating an operation procedure of updatingsystem information through a mobile station, which is in an idle mode,in a general communication system;

FIG. 5 is a conceptional view of a paging group that can be used in ageneral wireless communication system and a paging sub group that can beused in the embodiments of the present invention;

FIG. 6 is a diagram illustrating a paging interval to which a pagingsubframe that can be used in the embodiments of the present invention isapplied and an operation of a mobile station;

FIG. 7 is a diagram illustrating a paging subframe per paging sub groupaccording to one embodiment of the present invention;

FIG. 8 is a diagram illustrating an example of a method for updatingsystem information of a mobile station which is in an idle mode inaccordance with one embodiment of the present invention;

FIG. 9 is a diagram illustrating a location where a paging channel canbe transmitted in accordance with another embodiment of the presentinvention;

FIG. 10 is a diagram illustrating a paging interval when a pagingmessage is transmitted through a paging channel according to anotherembodiment of the present invention.

FIG. 11 is a diagram illustrating a location where a paging indicationbit in accordance with another embodiment of the present invention istransmitted.

FIG. 12 is a diagram illustrating a location where a paging message istransmitted according to another embodiment of the present invention.

FIG. 13 is a diagram illustrating an example of a location where apaging message is transmitted if paging indication bits are transmittedat different times per paging sub group in accordance with anotherembodiment of the present invention.

FIG. 14 is a diagram illustrating an example of a location where apaging message is transmitted if paging indication bits of a pluralityof paging sub groups are transmitted at the same time in accordance withanother embodiment of the present invention.

FIG. 15 is a diagram illustrating an example of a 1 bit pagingindication method in accordance with another embodiment of the presentinvention.

FIG. 16 is a diagram illustrating a method for transmitting a pagingmessage using bitmap type paging indication in accordance with anotherembodiment of the present invention.

FIG. 17 is a diagram illustrating an example that a paging indicationgrouping method in accordance with another embodiment of the presentinvention is used.

FIG. 18 is a diagram illustrating another example that paging indicationgrouping method in accordance with another embodiment of the presentinvention is used.

FIG. 19 is a diagram illustrating an example of a location where controlsignaling for a paging message in accordance with another embodiment ofthe present invention is transmitted.

FIG. 20 is a diagram illustrating an example that a paging cycle of amobile station is determined in a multi-level in accordance with thefurther embodiment of the present invention.

MODE FOR THE INVENTION

The present invention relates a wireless access system. Hereinafter,methods for paging a mobile station more efficiently in accordance withthe embodiments of the present invention will be described.

The following embodiments are achieved by combination of structuralelements and features of the present invention in a predetermined type.Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment.

In the description of drawings, procedures or steps that may make thesubject matter of the present invention obscure will be omitted, andprocedures or steps equivalent to the range that can be understood bythose skilled in the art will be omitted.

The embodiments of the present invention have been described based onthe data transmission and reception between a base station and a mobilestation. In this case, the base station means a terminal node of anetwork, which performs direct communication with the mobile station. Aspecific operation which is described as being performed by the basestation may be performed by an upper node of the base station as thecase may be.

In other words, it will be apparent that various operations performedfor communication with the mobile station in the network which includesa plurality of network nodes along with the base station may beperformed by the base station or network nodes other than the basestation. The base station may be replaced with terms such as a fixedstation, Node B, eNode B (eNB), and access point. Also, the mobilestation may be replaced with terms such as a user equipment (UE), asubscriber station (SS), a mobile subscriber station (MSS), and aterminal.

Furthermore, a transmitter means a fixed and/or mobile node thattransmits data service or voice service, and a receiver means a fixedand/or mobile node that receives data service or voice service.Accordingly, in an uplink, the mobile station could be a transmitter,and the base station could be a receiver. Likewise, in a downlink, themobile station could be a receiver, and the base station could be atransmitter.

Meanwhile, in the present invention, examples of the mobile stationinclude a personal digital assistant (PDA), a cellular phone, a personalcommunication service (PCS) phone, a global system for mobile (GSM)phone, a wideband CDMA (WCDMA) phone, and a mobile broadband system(MBS) phone. Also, examples of the mobile station include a personaldigital assistant (PDA), a hand-held PC, a notebook PC, a smart phone,and a multi mode-multi band (MM-MB) terminal.

In this case, the smart phone means a terminal having advantages of amobile communication terminal and a personal mobile terminal incombination. Namely, the smart phone can mean a terminal that datacommunication functions such as schedule management, facsimiletransmission and reception, and Internet access, which correspond tofunctions of the personal mobile terminal, are added to the mobilecommunication terminal. Also, the multi mode-multi band terminal means amobile terminal having a multi-modem chip to be operated in a portableInternet system and other mobile communication systems (for example,code division multiple access (CDMA) 2000 system, WCDMA system, etc.).

The embodiments according to the present invention may be implemented byvarious means, for example, hardware, firmware, software, or theircombination.

If the embodiment according to the present invention is implemented byhardware, the method according to the embodiments of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, etc.

If the embodiment according to the present invention is implemented byfirmware or software, the method according to the embodiments of thepresent invention may be implemented by a type of a module, a procedure,or a function, which performs functions or operations described asabove. A software code may be stored in a memory unit and then may bedriven by a processor. The memory unit may be located inside or outsidethe processor to transmit and receive data to and from the processorthrough various means which are well known.

The embodiments of the present invention can be supported by standarddocuments disclosed in at least one of wireless access systems, i.e.,IEEE 802 system, 3GPP system, 3GPP LTE system, and 3GPP2 system. Namely,among the embodiments of the present invention, steps or parts which arenot described to clarify technical spirits of the present invention canbe supported by the above standard documents. Also, all terminologiesdisclosed herein can be described by the above standard documents.Particularly, the embodiments of the present invention can be supportedby one or more of standard documents of the IEEE 802.16 system, i.e.,P802.16-2004, P802.16e-2005 and P802.16Rev2.

Hereinafter, the preferred embodiments according to the presentinvention will be described in detail with reference to the accompanyingdrawings. It is to be understood that the detailed description whichwill be disclosed together with the accompanying drawings is intended todescribe exemplary embodiments of the present invention and is notintended to describe unique embodiments by which the present inventioncan be carried.

Furthermore, specific terminologies hereinafter described are providedto assist understanding of the present invention, and variousmodifications can be made in the specific terminologies within the rangethat they do not depart from technical spirits of the present invention.

The present invention suggests a paging sub group that can be determinedseparately from a paging group classified by a geographic location toperform efficient paging. The paging sub group can also beMS-specifically determined (e.g., using MS identifier).

FIG. 5 is a conceptional view of a paging group that can be used in ageneral wireless communication system and a paging sub group that can beused in the embodiments of the present invention.

Referring to FIG. 5, when a mobile station moves from its paging groupregion (for example, P_G1) to another paging group region (P_G2), themobile station can perform location update. As a result, a new paginggroup identifier (PGID) is given to the mobile station, and the mobilestation belongs to a new paging group. However, since a paging sub groupis determined separately from the paging group defined in accordancewith the geographic location, the paging sub group can be maintainedregardless of a location of the mobile station. Accordingly, if pagingintervals of all mobile stations belonging to the same paging sub groupare determined equally, the mobile station can receive a paging messageat the same time of a paging cycle regardless of a change of the paginggroup, which is caused by movement of the mobile station.

For example, it is assumed that three mobile stations MS1, MS3, and MS5are established to a paging sub group 1 as illustrated in FIG. 5. If themobile station MS1 moves from the region P_G1 to the region P_G2, thepaging group of the mobile station MS1 can be updated through a locationupdate procedure. However, since the paging sub group is not relatedwith the geographic location, the mobile station may continuously bemaintained at the paging sub group 1. Hereinafter, a number of thepaging sub group can be used as the same meaning of paging sub group ID.Namely, paging sub group ID of the paging sub group 1 could be 1.

This paging sub group can be determined by mobile station ID (MSID)without separate signaling between a base station the mobile station. Inthis case, in order to determine the paging sub group, the mobilestation or the base station can identify a paging sub group of acorresponding mobile station by using a method of the following MathFigure 1.

Paging Sub Group ID=MS_ID modulo N  [Math Figure 1]

In the Math Figure 1, ‘N’ represents the number of paging sub groups,and can be transferred to the mobile station through system information.

Also, the paging sub group can be given to the mobile station by apaging controller or the base station through a deregistration command(DREG-CMD) message during idle mode entry or a ranging response(RNG-RSP) message during location update. This will be described withreference to Table 4.

Table 4 illustrates an example that paging sub group information isincluded in the deregistration command message or the ranging responsemessage that can be used in the embodiments of the present invention.

TABLE 4 Type 

Length 

Value 

Scope 

xxx 

x 

PAGING_CYCLE RNG-RSPDREG- PAGING_OFFSETPaging CMD 

Interval LengthPaging-group-ID Paging-sub-group-ID: mobile station isgrouped once more in sub group not geographical grouping.

Referring to Table 4, the base station can notify the mobile station ofthe paging sub group in such a manner that a paging sub group ID valueis added to a type length value (TLV) indicating paging information inthe deregistration command message or the ranging response message.

The present invention additionally suggests a paging subframe togetherwith the aforementioned paging subgroup. The paging subframe means asubframe where the paging message is transmitted. The paging subframewill be described with reference to FIG. 6.

FIG. 6 is a diagram illustrating a paging interval to which a pagingsubframe that can be used in the embodiments of the present invention isapplied and an operation of a mobile station.

In a general wireless communication system, a paging message monitoringinterval unit of the mobile station is a frame. However, if the pagingsubframe is applied as illustrated in FIG. 6, the mobile station canmonitor the paging message in a subframe unit. Accordingly, the mobilestation can save the power more efficiently. To this end, the TLVindicating paging information in the ranging response message or thederegistration command message transmitted from the base station to themobile station can be modified as illustrated in Table 5.

TABLE 5 Type 

Length 

Value 

Scope 

xxx 

x 

PAGING_CYCLE RNG-RSPDREG- PAGING_OFFSET: CMD determines the subframewithin the cycle in which the paging message is transmitted. Must besmaller than PAGING_CYCLE.Paging Interval Length: Max duration insubframes of paging interval. (default = 1)Paging- group-ID 

Referring to Table 5, paging offset and paging interval length can beestablished in a subframe unit.

According to the embodiments of the present invention, the mobilestations belonging to the same paging sub group can have the same paginginterval regardless of the paging group. Namely, the mobile stationsbelonging to different paging sub groups wake up at different pagingintervals and then identify the paging message while the mobile stationsbelonging to the same paging sub group wake up at the subframe of thesame paging interval and then identify the paging message.

Hereinafter, a method for efficiently transmitting a paging messageusing the aforementioned paging sub group and paging subframe will bedescribed in more detail.

1. Pacing Scheme Using Arbitrary Paging Subframe

According to one embodiment of the present invention, a paging messagecan be transmitted from a arbitrary subframe.

Generally, a listening interval (MS Listening Interval) of a mobilestation and a Paging Interval (BS paging interval) of a base station canbe defined in a frame unit through paging information that can betransmitted to the mobile station through a deregistration commandmessage or a ranging response message. However, in this embodiment, themobile station can receive a paging message by waking up at only aarbitrary subframe of a corresponding frame. At this time, mobilestations belonging to the same sub group can check for the pagingmessage by waking up at the same subframe. This will be described withreference to FIG. 7.

FIG. 7 is a diagram illustrating a paging subframe per paging sub groupaccording to one embodiment of the present invention.

In the following embodiments including the embodiment of FIG. 7, it isassumed that all paging sub groups belong to one paging group. It isalso assumed that all mobile stations belonging to the same paging grouphave the same paging cycle regardless of a paging interval (pagingsubframe) that can be defined by the paging sub group.

Referring to FIG. 7, mobile stations belonging to the paging sub group 1can receive the paging message by waking up at only a arbitrary pagingsubframe of the first frame even though the first frame of the pagingcycle is defined as the paging interval. Also, mobile stations belongingto the paging sub group 2 can receive the paging message by waking up atonly a arbitrary paging subframe of the fourth frame even though thefourth frame of the paging cycle is defined as the paging interval.

1-1. Method for Receiving a Paging Message from a Paging Subframe of aPaging Sub Group

A mobile station woken up at a arbitrary paging subframe can receive apaging message, and can decode the paging message to identify whetherthe presence of its paging information. Mobile stations belonging to thesame paging sub group receive the paging message from the same pagingsubframe.

For example, it is assumed that a mobile station MS1 belongs to a pagingsub group 1, and a paging subframe designated in the paging sub group 1is N. At this time, if there is no paging message transmitted from thepaging subframe of the MS1, i.e., subframe N, it may mean that allmobile stations belonging to the paging sub group 1 are not paged. Inthis case, all mobile stations belonging to the paging sub group 1 canenter an idle mode again.

By contrast, if there is a paging message transmitted at the pagingsubframe N, all mobile stations belonging to the paging sub group 1 canidentify the presence of its paging action code by decoding the pagingmessage. The mobile station which is commanded to perform networkreentry in accordance with the paging action code can be operated in anormal mode by waking up from the idle mode. The mobile station which iscommanded to perform location update can enter the idle mode afterperforming location update. The mobile station which has not receivedany command can enter the idle mode until next paging subframe.

1-2. Method for Updating System Information of a Paging Sub Group

If a paging message is transmitted from a arbitrary subframe, a mobilestation may have a difficulty to know the presence of system informationupdate at the time when the mobile station wakes up. For this reason,according to the related art, the mobile station has known a frame whereupdated system information is transmitted using a broadcast controlpointer information element (IE) which is transmitted to the mobilestation during a paging interval.

However, in an advanced system, for example, a system that periodicallytransmits system information, like a wireless communication systemsubject to the IEEE 802.16m standard, it is not required to notify themobile station of a location where system information will betransmitted. In the current IEEE 802.16m system, the base station cantransmit a broadcast channel (BCH) per 20 ms in a fixed location of asuperframe.

The BCH is divided into a primary BCH (PBCH) and a secondary BCH (SBCH).The PBCH can transmit network common information while the SBCH cantransmit cell specific information. The base station can transmit updateinformation of each system information block through the BCH, and canprovide scheduling information so that the mobile station receivesupdated broadcast information. In this case, there may be provided aplurality of system information blocks, and the system informationblocks may be regarded as a bundle of system information that can betransmitted at different cycles in accordance with a procedure.

Accordingly, this embodiment suggests that a field indicating thepresence of system information update is added to a paging message,instead of a broadcast control pointer information element according tothe related art, wherein the broadcast control pointer informationelement indicates a location of a frame where system information istransmitted. This field will be referred to as a system informationupdate indication (SIUI) field in the present invention. An example ofthis system information update indication field included in the pagingmessage will be described with reference to Table 6.

TABLE 6 Syntax Size (bit) Notes MOB_PAG-ADV_Message_format — — ( ){Management Message Type = 61 8 — Num_Paging_Group_IDs 8

For(i=0; — — i<Num_Paging_Group_IDs; i++){ Paging Group ID 16  — } — —System information update indication 1 Set to 1 if informationtransmitted

through BCH is changed. 

Num_MACs 8 Number of MS MAC addresses For(j=0; j<Num_MACs; j++){ — — MSMAC Address hash 24  The hash is obtained by computing a CRC24 on the MS48-bit MAC address. The polynomial for the calculation is 0x1864CFBAction Code 2 Paging action instruction to MS0b00 = No actionrequired0b01 = Perform ranging to establish location and acknowledgemessage0b10 = Enter network0b11 = reserved 

Reserved 

5 — } — — Padding Variable Padding bits to ensure octet aligned TLVEncoded Information Variable TLV-specific }

Referring to Table 6, the SIUI field can be set to a size of 1 bit. Themobile station which has received the paging message including the SIUIfield set to ‘1’ can receive the BCH from a superframe header (SFH) bywaking up at the first subframe of next superframe to receive systeminformation regardless of the paging interval. This will be describedwith reference to FIG. 8.

FIG. 8 is a diagram illustrating an example of a method for updatingsystem information of a mobile station which is in an idle mode inaccordance with one embodiment of the present invention.

Referring to FIG. 8, it is assumed that two different paging sub groups(paging sub group 1 and paging sub group 2) exist in the same paginggroup. It is also assumed that a paging subframe of the paging sub group1 is a arbitrary subframe of the first frame of the paging cycle, and apaging subframe of the paging sub group 2 is a arbitrary subframe of thefourth frame. At this time, the paging message including the SIUI fieldset to ‘1’ can be transmitted at each paging subframe of the paging subgroup 1 and the paging sub group 2. As a result, all mobile stationsbelonging to each paging sub group can update system information bywaking up at the first subframe of next superframe of a superframe wherethe paging message is transmitted and receiving the BCH.

If the SIUI field of the paging message transmitted to the pagingsubframe of each paging sub group is set to ‘0’ all mobile stations ofeach paging sub group can know that there is no update of systeminformation, and can continuously be operated in the idle mode.

Meanwhile, according to this embodiment, even though the mobile stationfails to decode the BCH, since the time when next BCH is transmitted isalways fixed, the mobile station does not need to stay up. Namely, eventhe mobile station fails to decode the BCH, the mobile station isoperated in the idle mode and then again wakes up after 20 ms to receivethe BCH. Also, the mobile station which has successfully decoded the BCHcan wake up at a subframe other than the paging subframe to receiveupdated system information in accordance with information provided fromthe BCH.

2. Paging Method Limiting Paging Subframe Using Subframe Including BCH

In the current wireless communication system, for example, the systemsubject to the IEEE 802.16m standard, one superframe has a length of 20ms, and each superframe which is transmitted includes a superframeheader (SFH). The superframe header includes a synchronous channel (SCH)and a broadcast channel (BCH). The BCH is a channel that transmitsbroadcast information, and can be divided into a PBCH and a SBCH. Systeminformation is also broadcast information, and can be transmitted to themobile station through the BCH. Accordingly, if a mobile station whichis in an idle mode wakes up at only a subframe where the BCH istransmitted, the mobile station can be operated more efficiently.

2-1. Paging Channel of Subframe Including BCH

According to this embodiment, a method for transmitting a paging messageat an SFH or a subframe where the SFH is transmitted, to a mobilestation through a paging channel (PCH) that can include a paging messagewill be described.

FIG. 9 is a diagram illustrating a location where a paging channel canbe transmitted in accordance with another embodiment of the presentinvention.

The paging channel can be included in the SFH as illustrated in FIG.9(a) or the BCH as illustrated in FIG. 9(b). Also, the paging channelmay be included in a predetermined location within a subframe where theSFH is transmitted, and may be transmitted to one of sub-packets of asecondary superframe header (SSFH).

FIG. 10 is a diagram illustrating a paging interval when a pagingmessage is transmitted through a paging channel according to anotherembodiment of the present invention.

It is assumed that two different paging sub groups (paging sub group 1and paging sub group 2) exist. As described above, it is preferable thata paging subframe is differently established per paging sub group, andmay be a subframe where the BCH is transmitted. Accordingly, the pagingsubframes can be established as the first subframes of differentsuperframes per paging sub group.

For example, as illustrated in FIG. 10, in case of the paging sub group1, the paging subframe can be established as the first subframe of thefirst superframe of the paging cycle. Also, in case of the paging subgroup 2, the paging subframe can be established as the first subframe ofthe second superframe of the paging cycle.

2-2. Transmission of Paging Indication Bit from Subframe Including BCH

In another aspect of this embodiment, a paging indication (PI) bit orfield indicating whether the paging message is transmitted can be onlytransmitted at the subframe where the BCH is transmitted, and the pagingmessage can be transmitted at another subframe. The paging indicationbit may have a length of 1 bit or multi-bits as occasion demands. Forexample, when a plurality of paging sub groups exist, one bit can beallocated to each paging sub group. The mobile station can receive thepaging message only if a paging indication bit allocated to its pagingsub group is set to ‘1’.

FIG. 11 is a diagram illustrating a location where a paging indicationbit in accordance with another embodiment of the present invention istransmitted.

The paging indication bit may be included in the SFH as illustrated inFIG. 11(a) or the BCH as illustrated in FIG. 11(b). Also, the pagingindication bit may be included in a predetermined location within thesubframe where the SFH is transmitted, as illustrated in FIG. 11(c), ormay be transmitted to one of sub-packets of a secondary superframeheader (SSFH).

Hereinafter, a location of a paging message that can be transmitted as apaging indication bit is set to ‘1’ and a method for notifying a mobilestation of the location of the paging message will be described.

2-2-1. Method for Notifying a Location where a Paging Message isTransmitted

If a paging indication bit of a paging sub group to which the mobilestation belongs is set to ‘1’, the mobile station should know the timewhen the paging message is transmitted and/or a location where thepaging message is transmitted, so as to receive the paging message.Also, the mobile station is operated in the idle mode until it reachesthe location where the paging message is transmitted, whereby the powercan be saved efficiently.

FIG. 12 is a diagram illustrating a location where a paging message istransmitted according to another embodiment of the present invention.

In a subframe including a superframe, it is assumed that a pagingindication bit of a specific paging sub group is set to ‘1’ and islocated to any one of locations described with reference to FIG. 11. Atthis time, a paging message of the specific paging sub group may beincluded in the same superframe as that where the paging indication bitis transmitted as illustrated in FIG. 12, or may be included in anothersuperframe within the same paging cycle. This will be described in moredetail with reference to FIG. 13 and FIG. 14.

FIG. 13 is a diagram illustrating an example of a location where apaging message is transmitted if paging indication bits are transmittedat different times per paging sub group according to another embodimentof the present invention.

Referring to FIG. 13, it is assumed that two different paging sub groups(paging sub group 1 and paging sub group 2) exist and paging indicationbits of respective paging sub groups are respectively transmittedthrough the first subframes of different superframes. At this time, thepaging message of each paging sub group is transmitted after apredetermined time, for example, i(i≧1) subframes, from the subframewhere the paging indication bit is transmitted.

Next, a case where a plurality of paging sub groups exist and pagingindication bits of respective paging sub groups are transmitted at thesame time will be described.

The paging indication bits may have a bitmap type to simultaneouslynotify the mobile stations of the respective paging sub groups whetherthe paging message of each of the plurality of paging sub groups istransmitted. For example, if the paging messages of the paging sub group1 and the paging sub group 2 are only transmitted, the paging indicationbits of the paging groups are arranged starting from the mostsignificant bit (MSB) of the bitmap in the order from the first pagingsub group to the last paging sub group, thereby having a type of ‘110 .. . 0’. The location where the paging message is transmitted when thisbitmap is used will be described with reference to FIG. 14.

FIG. 14 is a diagram illustrating an example of a location where apaging message is transmitted if paging indication bits of a pluralityof paging sub groups are transmitted at the same time according toanother embodiment of the present invention.

In FIG. 14, it is assumed that N paging sub groups (paging sub group 1,paging sub group 2, . . . paging sub group N) exist. It is also assumedthat paging indication bits indicating whether the paging message ofeach paging sub group is transmitted are transmitted through the firstsubframe of each paging cycle.

If the paging indication bit is set to ‘110 . . . 0’ in the firstsubframe of the first paging cycle, it represents that only the pagingmessages for the paging sub group 1 and the paging sub group 2 aretransmitted. In this case, the subframe where the paging message of thepaging sub group having the paging indication bit set to 1 istransmitted can be determined using a number of the paging sub group(i.e., paging sub group ID). Namely, the paging message of the pagingsub group 1 can be transmitted from the ith subframe of the subframeswhere the paging indication bit is transmitted. Also, the paging messageof the paging sub group 2 can be transmitted from the i+8th subframe ofthe subframes where the paging indication bit is transmitted.

If the paging indication bit is set to ‘11 . . . 1’ as illustrated inthe second paging cycle of FIG. 14, in case of the paging sub group N,the paging indication bit can be transmitted from the i+8(N−1)thsubframe of the subframes where the paging indication bit istransmitted. In this case, the transmission intervals of the pagingmessage are spaced apart from each other by 8 subframes whenever thepaging sub group increases by 1. However, the transmission intervals areonly exemplary and may be modified if necessary.

As described above, although the location where the paging message ofthe paging indication bit is transmitted may be defined in accordancewith a previously determined rule, the location where the paging messageis transmitted may be defined through predetermined signaling. Forexample, information of the location where the paging message istransmitted can be transmitted together with the paging indication bit.

2-2-2. Method for Setting a Paging Indication Bit

Hereinafter, a method for setting a paging indication bit in accordancewith various sizes and formats will be described.

2-2-2-1. 1 Bit Paging Indication Method

If a 1 bit paging indication method is used, whether a paging message ofone paging sub group is transmitted can be identified per superframe.Accordingly, if the paging indication bit is transmitted through any oneof the locations described with reference to FIG. 11, it is preferablethat the paging indication bit is transmitted through differentsuperframes per paging sub group. This will be described with referenceto FIG. 15.

FIG. 15 is a diagram illustrating an example of a 1 bit pagingindication method in accordance with another embodiment of the presentinvention.

Referring to FIG. 15, a paging indication bit of the paging sub group 1can be transmitted from the first superframe of the paging cycle, and apaging indication bit of the paging sub group 2 can be transmitted fromthe second superframe of the paging cycle. All mobile stations belongingto each paging sub group can wake up to receive the paging message onlyif the paging indication bit of the paging sub group to which the mobilestations belong is set to 1. It is preferable that the as any one of thelocations described with reference to FIG. 11 is designated as thelocation where the paging indication bit is transmitted. Also, thelocation where the paging indication bit is transmitted can bedesignated through one of the methods described in 2-2-1.

2-2-2-2. n Bit Paging Indication Method

In this embodiment, paging intervals for receiving paging indication(PI) in all mobile stations belonging to the same paging group can beestablished equally. Also, in this embodiment, paging information thatincludes paging cycle, paging offset, paging interval length and pagingsub group number can be broadcasted through system information. Thiswill be described with reference to Table 7.

Table 7 illustrates an example that paging information related toanother embodiment of the present invention is broadcasted throughsystem information.

TABLE 7 Type 

Length 

Value 

Scope 

xxx 

x 

PAGING_CYCLE RNG-RSPDREG- PAGING_OFFSETPaging CMDSystem IntervalLengthPaging- Information group-ID Paging sub (BCH) 

group number: the number of paging sub groups belonging to paging group

Referring to Table 7, paging information transferred to the mobilestation through the ranging response message or the deregistrationcommand message in the general wireless communication system can beincluded in the system information so that the information can betransmitted to the mobile station through the BCH. Also, the paginginformation can further include information of the number of paging subgroups.

In this way, all mobile stations can identify the paging subframe wherepaging indication (PI) is transmitted, through the broadcasted paginginformation. Accordingly, each mobile station belonging to each pagingsub group can identify paging indication of its paging sub group number,and can receive the paging message through any one of the methodsdescribed in 2-2-1 if the paging message of its paging sub group istransmitted.

Also, in this embodiment, paging indication (PI) indicating whether thepaging message of the mobile station belonging to each paging sub groupis transmitted can have an n-bit bitmap type. This will be describedwith reference to FIG. 16.

FIG. 16 is a diagram illustrating a method for transmitting a pagingmessage using bitmap type paging indication in accordance with anotherembodiment of the present invention.

In FIG. 16, it is assumed that N paging sub groups exist and N-bitpaging indication is transmitted to the mobile stations, which belong toeach paging sub group, through the first subframe of each paging cycle.It is also assumed that the location where the paging message of eachpaging sub group is designated through any one of the methods describedin 2-2-1.

In the first paging cycle, a paging indication bitmap of ‘10 . . . 0’indicating that the paging message of the paging sub group 1 is onlytransmitted is transmitted to each paging sub group. As a result, allmobile stations belonging to the paging sub group 1 can receive thepaging message by waking up in the previously determined location.

In the second paging cycle, a paging indication bitmap of ‘010 . . . 1’indicating that the paging messages of the paging sub group 2 and thepaging sub group N are transmitted is transmitted to each paging subgroup. As a result, the mobile stations belonging to the paging subgroup 2 and the paging sub group N can receive the paging message bywaking up at the time when the paging message of the correspondingpaging sub group is transmitted.

2-2-2-3. Grouping Method of n Bit Paging Indication

According to the aforementioned n-bit bitmap paging indication methodusing a bitmap of multi-bits, mobile stations belonging to all pagingsub groups of one paging group can identify paging indication by wakingup at the same paging interval. However, if paging subframes where thepaging indication using the multi-bit bitmap is transmitted are alsogrouped, all the mobile stations of the paging group may not wake up atthe same time.

In this embodiment, N paging sub groups belonging to one paging groupcan be divided into M paging indication groups. Namely, mobile stationsbelonging to N/M paging sub groups can simultaneously identify pagingindication (PI) of N/M-bit size by waking up at the same paging interval(listening interval). In this case, N is divided by M when N is amultiple of M and the paging sub groups are allocated to the pagingindication group at the same rate. However, the paging indication groupsmethod can be used even though the paging sub groups are not allocatedto the paging indication group at the same rate.

The mobile stations of each paging group can wake up at the pagingsubframe determined per paging sub group to receive the paging messageonly if paging indication of the paging sub groups to which the mobilestations of each paging group belong is set. This will be described withreference to FIG. 17.

FIG. 17 is a diagram illustrating an example that a paging indicationgrouping method in accordance with another embodiment of the presentinvention is used.

Referring to FIG. 17, one paging group is divided into four paging subgroups, wherein the paging sub groups 1 and 2 are included in the pagingindication group 1 and the paging sub groups 3 and 4 are included in thepaging indication group 2. In this case, paging indication of eachpaging indication group can be transmitted through the first subframesof different superframes. The mobile stations of the paging sub groupsbelonging to the same paging indication group can be established to havethe same paging interval (or listening interval). Namely, supposing thatthe paging sub groups 1 and 2 belong to the paging indication group 1and the paging sub groups 3 and 4 belong to the paging indication group2, the mobile stations of the idle mode, which belong to each pagingindication group, identify the same paging indication bit with the samelistening interval.

In this case, the paging interval or the listening interval could be asuperframe unit, and the mobile stations of the idle mode can identifythe paging indication bit at the SFH which corresponds to a start partof the listening interval. Also, the mobile stations of the idle modecan identify the paging indication bit and at the same time receivesystem information transmitted through the SFH or the subframe includingSFH.

Furthermore, the mobile stations of the idle mode may identify thepaging indication bit through system information. The mobile stationswhich have identified the paging indication bit can receive the pagingmessage by waking up at the paging subframe or frame where the pagingmessage of their paging sub group is transmitted, only if the pagingindication bit of the paging sub group to which each mobile station ofthe idle mode belongs is set.

For example, in the first paging cycle of FIG. 17, the paging indicationbit of the paging indication group 1 is set to 10 through the firstsubframe of the first superframe. All mobile stations of the paging subgroups 1 and 2 receive the paging indication bit, and identify whetherthe paging message is transmitted to the paging sub group to which theybelong. Since the paging indication bit is set to 10, the mobilestations belonging to the paging sub group 1 can receive the pagingmessage at the previously determined subframe, and the mobile stationsbelonging to the paging sub group 2 continue to be operated in the idlemode.

The mobile stations of the paging sub groups 3 and 4 belonging to thepaging indication group 2 can receive the paging indication bit of thepaging indication group 2 from the first subframe of the secondsuperframe of the first paging cycle. Since the paging indication bit ofthe paging indication group 2 is set to 00, the mobile stationsbelonging to the paging indication group 2 can identify that the pagingmessage is not transmitted, and can continuously be operated in the idlemode.

In case of the second paging cycle, since the paging indication bit ofthe paging indication group 2 is 01 in the first subframe, only themobile stations belonging to the paging sub group 2 can receive thepaging message at the previously determined paging subframe. The mobilestations belonging to the paging sub groups 3 and 4 of the pagingindication group 2 can receive the paging indication bit of the pagingindication group 2 from the first subframe of the second superframe ofthe first paging cycle. Since the paging indication bit of the pagingindication group 2 is set to 11, all the mobile stations belonging tothe paging indication group 2 can receive the paging message from thepaging subframe previously established for each paging sub group.

FIG. 18 is a diagram illustrating another example that paging indicationgrouping method in accordance with another embodiment of the presentinvention is used.

As illustrated in FIG. 18, if four paging sub groups exist within thepaging group, the paging message of each paging sub group can beallocated one by one in a frame unit within one superframe. Namely, ifthe four paging sub groups belong to one paging indication group, thepaging message of each paging sub group can be allocated either one byone in due order per frame or through modulo operation.

2-2-2-4. Method for Transmitting a Paging Indication Bit Map ThroughSSFH

In the IEEE 802.16m system, the SFH is divided into a primary superframeheader (PSFH) and a secondary superframe header (SSFH). Although thePSFH is transmitted per superframe, the SSFH may not be transmitted persuperframe. Information transmitted through the SSFH is divided intodifferent sub-packets and then can be included in the SSFH. According tothis embodiment, a method for transmitting a paging indicator having asimilar function to that of the aforementioned paging indication bitthrough S-SFH SP5 IE (Paging Sub-Packet IE) that can be used to transferpaging information will be disclosed.

Hereinafter, contents that can be included in the S-SFH SP5 IE will bedescribed with reference to Table 8 to Table 10. In Table 8 to Table 10,it is assumed that four paging sub groups exist per paging group.

First of all, Table 8 illustrates an example of contents that can beincluded in the S-SFH SP5 IE in accordance with another embodiment ofthe present invention.

TABLE 8 Syntax Size (bit) Notes S-SFH SP5 IE format ( ) { 

N_PGID 3 Number of PGIDs in the sub-packets PGID List 16 * N_PGID Listof Paging group IDs For (i=0;i<N_PGID; i++){

Paging group ID TBD

Paging indicator 4

}

}

Referring to Table 8, since four paging sub groups are included in onepaging ID, a paging indicator field is established to have a size offour bits.

Table 9 illustrates another example of contents that can be included inthe S-SFH SP5 IE in accordance with another embodiment of the presentinvention.

TABLE 9 Syntax Size (bit) Notes S-SFH SP5 IE format ( ) { 

N_PGID 3 Number of PGIDs in the sub-packets Paging Indicator Usage 1 0b= 1 Paging indicator Flag bitmap is present0b = 0 paging indicatorbitmap is absent PGID List 16 * N_PGID List of Paging group IDs If(Paging Indicator Usage

Flag ==1) { For (i=0;i<N_PGID; i++){

Paging group ID TBD

Paging indicator 4

}

}

}

Referring to Table 9, a Paging Indicator Usage Flag field is set to 0when the paging messages of all paging groups transmitted within thecorresponding superframe are not transmitted at all.

Table 10 illustrates other example of contents that can be included inthe S-SFH SP5 IE in accordance with another embodiment of the presentinvention.

TABLE 10 Syntax Size (bit) Notes S-SFH SP5 IE format ( ) { 

N_PGID 3 Number of PGIDs in the sub-packets PGID List 16 * N_PGID 

List of Paging group IDs For (i=0; i<N_PGID; i++){

Paging Indicator Usage Flag 1 0b = 1 Paging indicator bitmap ispresent0b = 0 paging indicator bitmap is absent If( Paging IndicatorUsage

Flag ==1) { Paging group ID TBD

Paging indicator 4

}

}

}

Referring to Table 10, unlike Table 9, a paging indicator usage flag canrespectively be applied to each paging group instead of all paginggroups transmitted within the corresponding superframe.

3. Method for Detecting a Paging Message Using Paging CID

According to still another embodiment, a method for detecting a pagingmessage using paging CID is disclosed, in which decoding overhead of amobile station can be reduced and the mobile station can detect thepaging message more quickly.

In the general wireless communication system, broadcast CID is used totransmit the paging message. However, in this embodiment, a method fortransmitting a paging message using paging CID dedicated for the pagingmessage is suggested. In this case, even if one CRC is attached to allsub-maps and the mobile station should perform blind decoding, mobilestations of an idle mode and mobile stations of a normal mode can beoperated effectively. Namely, only the mobile stations of the idle modecan receive the message transmitted using the paging CID while themobile stations of the normal mode do not receive the messagetransmitted using the paging CID. Accordingly, overall system throughputcan be improved and power consumption of the mobile station can bereduced.

Meanwhile, if a blind decoding scheme is used, in this embodiment, amethod for transmitting control signaling for a paging message in afixed location (for example, first location) of a sub-map can be used.Namely, the paging message can be transmitted from a paging subframeusing a format of a fixed size in a fixed location of a sub-map.Accordingly, it is possible to reduce decoding overhead that may occuras the mobile station performs blind decoding for all sub-maps to detectcontrol signaling. If the mobile station fails to perform blind decodingfor control signaling of a previously set size in a fixed location, itcan be determined that there is no paging message in the correspondingpaging subframe. Accordingly, the mobile station can enter the idle modedirectly without blind decoding for the other sub-map.

Accordingly, in this method, since the mobile station of the idle modedecodes only a part which includes control information of the pagingmessage from the sub-map of the paging subframe, it is effective insaving the power of the mobile station. This will be described withreference to FIG. 19.

FIG. 19 is a diagram illustrating an example of a location where controlsignaling for a paging message in accordance with another embodiment ofthe present invention is transmitted.

Referring to FIG. 19, supposing that the fourth subframe is a pagingsubframe, control signaling of the paging message can be transmitted tothe mobile station through a sub-map of the corresponding subframe andis preferably located at the foremost part of the sub-map. In this case,it is efficient in that the mobile station can determine the presence ofthe paging message by decoding only the foremost part of the sub-map ofthe paging subframe.

4. Multi-Level Paging Cycle

According to a further embodiment, there is provided a method forestablishing a paging cycle (PAGING_CYCLE) value in a multi-level,wherein the paging cycle value is one of parameters related to pagingthat can be set between the mobile station and the base station.

In case of the mobile station which is not paged for a long time, powerconsumption and paging overhead can be reduced if the paging cycle ofthe mobile station increases to a maximum value, which is previouslyestablished, through a predetermined level. This will be described withreference to FIG. 20.

FIG. 20 is a diagram illustrating an example that a paging cycle of amobile station is established in a multi-level in accordance with thefurther embodiment of the present invention.

First of all, as illustrated in FIG. 20(a), the paging cycle of themobile station is classified into three levels. If the mobile station isnot paged for a time corresponding to one level, a time equivalent totwice of a previous level can be established as a paging cycle of nextlevel. At this time, it is assumed that the paging cycle of the firstlevel is 100 ms and the maximum paging cycle is 400 ms corresponding tothe third level.

If the mobile station is not paged for the paging interval of the firstpaging cycle of 100 ms after entering the idle mode, the mobile stationperforms the operation of the idle mode in a paging cycle of 200 ms ofthe second level. If the mobile station is not paged for the paginginterval even by the paging cycle of the second level, the mobilestation performs the operation of the idle mode in a paging cycle of 400ms of the third level. If the mobile station is not paged for the paginginterval even by the paging cycle of the third level, the mobile stationperforms the operation of the idle mode in a state that the paging cycleof the third level corresponding to the maximum paging cycle ismaintained.

Next, if the mobile station is not paged for the twice-repetitioninterval of the paging cycle of one level as illustrated in FIG. 20(b),the mobile station can be operated in accordance with the paging cycleof next level. Of course, the number of repetition times can be changedin accordance with user s requirements or system status until the pagingcycle of one level is converted to that of next level.

The maximum value of the aforementioned paging cycle can be transmittedto the mobile station in a type illustrated in Table 11.

Table 11 illustrates an example of contents included in a messagenotifying the mobile station of the maximum paging cycle of themulti-level paging cycle in accordance with the further embodiment ofthe present invention.

TABLE 11 Type Length 

Value 

Scope 

Xxx 

x 

PAGING_CYCLE MAX RNG-RSPDREG-CMD PAGING_CYCLE: Maximum value of (SystemInformation) D PAGING_CYCLEPAGING_OFFSETPaging IntervalLengthPaging-group-ID 

Referring to Table 11, the maximum paging cycle (MAX PAGING_CYCLE) valuecan be added to the paging information that can be used in the generalwireless communication system. In this case, it is preferable that themaximum paging cycle value is equal to or greater than a paging cycle(PAGING_CYCLE) parameter value. Although the paging information may betransmitted to the mobile station through the ranging response messageor the deregistration command message, the paging information may bebroadcasted through system information as described in 2-2-2-2.

In this embodiment, the paging cycle increases by a predetermined rateor predetermined value if a paging cycle of a rule previously agreedbetween the mobile station and the base station, for example, a giventime or a given number of times, passes. If the paging cycle reaches themaximum value, the maximum value can be maintained. Also, an increasevalue and an increase condition of the paging cycle may be establishedexplicitly through a message unicasted between the mobile station andthe base station.

As a still further embodiment of the present invention, the mobilestation and the base station through which the embodiments of thepresent invention can be performed will be described with reference toFIG. 5 to FIG. 20.

The mobile station can be operated as a transmitter in the uplink, andcan be operated as a receiver in the downlink. Also, the base stationcan be operated as a receiver in the uplink, and can be operated as atransmitter in the downlink. Namely, the mobile station and the basestation can include a transmitter and a receiver to transmit informationor data.

The transmitter and the receiver can include processor, module, part,and/or means for performing the embodiments of the present invention.Particularly, the transmitter and the receiver can include a module(means) for encoding a message, a module for decoding the encodedmessage, and an antenna for transmitting and receiving the message.

The mobile station used in the embodiments of the present invention caninclude a low power radio frequency (RF)/intermediate frequency (IF)module. Also, the mobile station can include a means, module or part forperforming controller function, medium access control (MAC) framevariable control function according to service characteristics and radiowave condition, handover function, authentication and encryptionfunction, packet modulation and demodulation function for datatransmission, quick packet channel coding function, and real-time modemcontrol function, thereby performing the aforementioned embodiments ofthe present invention.

The base station can transmit data received from an upper layer to themobile station by wireless or wire. The base station can include a lowpower RF/IF module. Also, the base station can include a means, moduleor part for performing controller function, orthogonal frequencydivision multiple access (OFDMA) packet scheduling, time division duplex(TDD) packet scheduling and channel multiplexing function, medium accesscontrol (MAC) frame variable control function according to servicecharacteristics and radio wave condition, handover function,authentication and encryption function, packet modulation anddemodulation function for data transmission, quick packet channel codingfunction, and real-time modem control function, thereby performing theaforementioned embodiments of the present invention.

It will be apparent to those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit and essential characteristics of the invention. Thus, theabove embodiments are to be considered in all respects as illustrativeand not restrictive. The scope of the invention should be determined byreasonable interpretation of the appended claims and all change whichcomes within the equivalent scope of the invention are included in thescope of the invention.

INDUSTRIAL APPLICABILITY

The embodiments of the present invention can be applied to variouswireless access systems. Examples of various wireless access systemsinclude 3GPP (3rd Generation Partnership Project) system, 3GPP2 systemand/or IEEE 802.xx (Institute of Electrical and Electronic Engineers802) system. The embodiments of the present invention can be applied toall technical fields to which the various access systems are applied, aswell as the various access systems.

1-19. (canceled)
 20. A method of receiving a message by a terminal, themethod comprising: receiving indication information included in asignaling part of a frame via a broadcast channel, wherein theindication information indicates whether the message is included in afirst part of the frame other than the signaling part of the frame,wherein when the indication information is set to a first value, themessage is included in the first part of the frame and when theindication information is set to a second value, the message is notincluded in the first part of the frame; when the indication informationis set to the first value, obtaining the message in the first part ofthe frame according to the indication information, wherein the messageincludes update information indicating whether broadcast information ischanged; and acquiring the changed broadcast information when the updateinformation indicates that the broadcast information is changed, whereinboth the indication information and the message are included in theframe, wherein the signaling part is located in front of the first partin the frame, wherein the first part of the frame is transmitted in asubframe unit, and wherein interval information which is set in thesubframe unit is included in the signaling part of the frame.
 21. Themethod of claim 20, wherein the broadcast information is receivedperiodically.
 22. The method of claim 20, wherein a location where themessage in the frame is received is defined in accordance with apreviously determined rule.